2 files changed, 17 insertions, 14 deletions

diff --git a/cbuf.c b/cbuf.c
index 966349d..0917627 100644
--- a/cbuf.c
+++ b/cbuf.c
@@ -27,16 +27,17 @@
  */
 
 #include <assert.h>
+#include <stddef.h>
 
 #include "cbuf.h"
 #include "error.h"
 #include "macros.h"
 
 /* Negative close to 0 so that an overflow occurs early */
-#define CBUF_INIT_INDEX ((unsigned long)-500)
+#define CBUF_INIT_INDEX ((size_t)-500)
 
 void
-cbuf_init(struct cbuf *cbuf, char *buf, unsigned long capacity)
+cbuf_init(struct cbuf *cbuf, char *buf, size_t capacity)
 {
     assert(ISP2(capacity));
 
@@ -46,8 +47,8 @@ cbuf_init(struct cbuf *cbuf, char *buf, unsigned long capacity)
     cbuf->end = cbuf->start;
 }
 
-static unsigned long
-cbuf_index(const struct cbuf *cbuf, unsigned long abs_index)
+static size_t
+cbuf_index(const struct cbuf *cbuf, size_t abs_index)
 {
     return abs_index & (cbuf->capacity - 1);
 }
@@ -77,7 +78,7 @@ cbuf_pop(struct cbuf *cbuf, char *bytep)
 }
 
 int
-cbuf_read(const struct cbuf *cbuf, unsigned long index, char *bytep)
+cbuf_read(const struct cbuf *cbuf, size_t index, char *bytep)
 {
     /* Mind integer overflows */
     if ((cbuf->end - index - 1) >= cbuf_size(cbuf)) {
diff --git a/cbuf.h b/cbuf.h
index 00a9053..bfc728b 100644
--- a/cbuf.h
+++ b/cbuf.h
@@ -31,6 +31,8 @@
 #ifndef _CBUF_H
 #define _CBUF_H
 
+#include <stddef.h>
+
 /*
  * Circular buffer descriptor.
  *
@@ -39,30 +41,30 @@
  */
 struct cbuf {
     char *buf;
-    unsigned long capacity;
-    unsigned long start;
-    unsigned long end;
+    size_t capacity;
+    size_t start;
+    size_t end;
 };
 
-static inline unsigned long
+static inline size_t
 cbuf_capacity(const struct cbuf *cbuf)
 {
     return cbuf->capacity;
 }
 
-static inline unsigned long
+static inline size_t
 cbuf_start(const struct cbuf *cbuf)
 {
     return cbuf->start;
 }
 
-static inline unsigned long
+static inline size_t
 cbuf_end(const struct cbuf *cbuf)
 {
     return cbuf->end;
 }
 
-static inline unsigned long
+static inline size_t
 cbuf_size(const struct cbuf *cbuf)
 {
     return cbuf->end - cbuf->start;
@@ -80,7 +82,7 @@ cbuf_clear(struct cbuf *cbuf)
  * The descriptor is set to use the given buffer for storage. Capacity
  * must be a power-of-two.
  */
-void cbuf_init(struct cbuf *cbuf, char *buf, unsigned long capacity);
+void cbuf_init(struct cbuf *cbuf, char *buf, size_t capacity);
 
 /*
  * Append a byte to a circular buffer.
@@ -106,6 +108,6 @@ int cbuf_pop(struct cbuf *cbuf, char *bytep);
  * Otherwise the byte is stored at the bytep address and 0 is returned.
  * The buffer isn't changed by this operation.
  */
-int cbuf_read(const struct cbuf *cbuf, unsigned long index, char *bytep);
+int cbuf_read(const struct cbuf *cbuf, size_t index, char *bytep);
 
 #endif /* _CBUF_H */